Proteins in the body are continuously degraded and synthesized by processes that require energy. In a body, a positive nitrogen balance occurs when the total nitrogen excreted in the urine, feces and sweat is less than the total nitrogen ingested. This positive nitrogen balance must exist for new tissue to be synthesized.
Most Americans consume a 12 weight percent protein diet, while most bodybuilders consume upwards of a 25% to 30% protein diet. This bodybuilding subgroup, in order to add lean body mass to their body, must consume additional amounts of protein in order to maintain a positive nitrogen balance so the body can generate new tissue. The average sedentary adult, however, only needs to consume on the order of 30 to 60 grams of dietary protein per day to balance amino acids consumed by the body, assuming a normal caloric intake. Factors associated with increased protein requirements include the following: growth of skeletal tissue or growth during puberty, etc., low calorie diets, endurance training, strength training, high muscle-to-fat ratio, and vegetarian diets.
If protein requirements of the body are not met by dietary sources, a nitrogen deficit may develop. This deficit results from urinary nitrogen excretion exceeding the amounts of dietary protein being consumed. The increase in urinary nitrogen excretion is caused by catabolism of proteins to provide the essential amino acids that are not being supplied by dietary sources. A negative nitrogen balance is caused by: the consumption of an insufficient quantity of essential amino acid containing protein or the consumption of protein lacking essential amino acids. In addition to appropriate quantity and quality of protein consumed, sufficient energy must also be consumed to support protein metabolism, else a negative nitrogen balance will develop regardless of the quality or quantity of protein consumed.
The most recent indications are that dietary protein in excess of the current recommended dietary allowance (0.8 grams of protein per kilogram of body weight per day) is likely needed for optimal muscle growth. The current recommended daily allowance is also inadequate for an athlete who trains daily, is still growing, and/or who is in a peak performance training regime. Indeed, the benefit of increased levels of dietary protein appears to plateau at intakes well below the levels typically consumed by many athletes. Therefore, while a diet high in protein is beneficial for muscle growth, it may only be beneficial to an extent. Once a certain intake level is reached, additional protein intake does not help build muscle mass. Little progress has been made in overcoming this maximal protein intake plateau through dietary modifications.
Maslinic acid (2-α,3-β-dihydroxyolean-12-en-28-oic acid) and structurally related oleanolic acid (3-β-hydroxyolean-12-en-28-oic acid) are widely distributed in plants. These pentacyclic tri-terpenoid acids (hereafter “PTAs”) are particularly abundant in the surface wax on the fruits and leaves of olive trees (Olea europaea) (Bianchi et al., Phytochem., 37(1), pp. 205-207, 1994) and solid waste from olive oil production (García-Granados et al., J. Chem. Res.; 2000 (2) pp. 56-57). Loquat fruit (Eriobotrya japonica) also has considerable quantities of these terpenoid acids.
Maslinic acid has been studied as it relates to cell-growth changes in the liver and white muscle in different situations due to differences in protein turnover rates and nucleic acid concentrations (Peragón et al., Comp. Biochem. Physio. Part C: Toxicology, 147(2), pp. 158-167, 2008). These terpenoid acids have been implicated as protease inhibitors that may suppress cancers yet promote astrocytic tumors (Martin et al., Can. Res., 67, pp. 3741, 2007).
Dietary maslinic acid induces higher protein synthesis in trout to sustain the generation of new cells and to be exported for different purposes. At the same time, maslinic acid stimulated the protein degradation rate, both in relative (KD) and absolute (AD) terms. The protein-efficiency ratio (PER) and feed-efficiency ratio (FER) both increased in trout fed maslinic acid concentration at 250 mg kg-1, with respect to a control. (Peragón et al., Can. J. Fish Aquat. Sci., 55(3), pp. 649-659 (1998).
The presence of abundant and well-organized rough endoplasmic reticula as seen by electron microscopy in the hepatocytes of trout fed 250 mg kg-1 maslinic acid confirms the prolific biosynthesis of exportable proteins. (Ibid.) The higher number of white-muscle cells, mediated by increase in the DNA, RNA, and protein content, seems to result from a stimulation of the biosynthesis pathways of all this macromolecules similar to those produced by a growth factor. Maslinic acid fed to trout at 25 and 250 mg kg-1 increased the protein-synthesis rate (KS and AS), while no significant changes were found in fractional protein-degradation rate (KD) and only a minor increase in the absolute protein-degradation rate (AD). These changes in protein-turnover rates explain the high protein-accumulation rates (KG and AG) found in trout fed with maslinic acid. (Ibid.) Conflicting studies found 80 mg kg-1 to retard juvenile dentex fish growth (Hidalgo et al., Aquacult. Nutri., 12(4), pp. 256-266, 2006).
In relation to these results, it has been reported that maslinic acid leads to a high accumulation of glycogen in rainbow trout liver (Fernández-Navarro et al., 2006) and can also act as a new type of glycogen phosphorylase inhibitor (Wen et al., 2005; 2006), the enzyme responsible for glycogen degradation in liver and white muscle.
Thus, there exists a need for a dietary supplement containing PTAs to promote building of muscle mass in a high protein content diet.